On Fri, Aug 21, 2009 at 12:34:28PM -0700, Josh Stone wrote:> On 08/21/2009 10:52 AM, Jason Baron wrote:> > this means that when CONFIG_EVENT_TRACING is set, the 'generic' syscall> > enter/exit will show up as events in the debugfs, but enabling them> > wouldn't do anything. I think we should simply drop the> > 'CONFIG_FTRACE_SYSCALLS' 'ifdef' and 'else' clause. That will give us> > what we want - tying these callbacks directly to tracepoint.> > But only x86 and s390 have TIF_SYSCALL_FTRACE, while kernel/tracepoint.c> must still compile everywhere that has CONFIG_TRACEPOINTS=y.> > Maybe it would be better to make that #ifdef TIF_SYSCALL_FTRACE, and> then also #ifdef the TRACE_EVENT declaration, so it will only show up on> kernels that actually support it.

Instead of testing TIF_SYSCALL_FTRACE, I'd suggest testing HAVE_FTRACE_SYSCALLS.This makes more sense and is more verbose wrt its role in the conditionnal definition,given its macro name.

> Also, since this event is now usable outside of ftrace, would you object> to renaming the flag TIF_SYSCALL_TRACEPOINT?> > Josh